The bombings were the deadliest terrorist attacks in Spanish history, and the worst in Europe since the 1988 bombing of Pan Am flight 103 over Lockerbie, Scotland.

In September 2004, a three-day siege at a school in Beslan, North Ossetia, ended in the deaths of 334 people, including more than 180 children.

In August 2007, at least 500 people died and 1,500 were injured during car bomb attacks on Yazidi communities near Mosul, Iraq.

In December the following year, members of the Lord’s Resistance Army, a Ugandan rebel group, attacked several villages in the Democratic Republic of the Congo. The rebels surrounded people celebrating Christmas, killing more than 620, according to media reports.

In May 2014, Boko Haram militants attacked the towns of Gamboru and Ngala in Nigeria, killing more than 300 residents over 12 hours.

Two months later, an Islamic State attack on Iraqi air force cadets at Camp Speicher in Tikrit killed more than 1,500 Shia and non-Muslim cadets.

In July 2016, at least 340 people were killed, and hundreds injured, in a series of coordinated bomb attacks carried out by Isis in the predominantly Shia district of Karrada in Baghdad.

In October 2017, about 600 people were killed and more than 300 injured in suicide truck bombing in Mogadishu, Somalia.

The following month, about 40 gunmen attacked a mosque near the city of Bir al-Abed in Egypt. More than 200 people were killed, making it Egypt’s deadliest terrorist attack.

Last July, at least 258 people died after Isis militants carried out suicide bombings and gun attacks in and around the Syrian city of Sweida.